Resistance to freezing and thawing of mortar specimens made from sulphoaluminate–belite cement

[摘要] Resistance to freezing and thawing of mortar specimens made from sulphoaluminate–belite cement (M–SAB) is compared with that of mortars made from portland cement (M–PC). The results suggest that larger median radius of the pores and total porosity of M–SAB compared to those of M–PC are primarily caused by the rapid setting of the SAB cement. The `coarsening’ of pore structure of mortar specimens under action of freezing and thawing is proved by the increase in the macropores portion, median pore radius, and total porosity values. This process is more intense in M–SAB. The effect of the frost attack is confirmed by lower compressive strength and dynamic modulus of elasticity on the one hand and higher absorption capacity, expansion, and crack propagation of M–SAB compared with those of M–PC on the other hand. Besides the decreased frost resistance of M–SAB as compared with that of M–PC, unsatisfactory passivation of steel in M–SAB was found. The reason of this fact is the pH value decrease to less than 11.5 of the M–SAB extract.

[学科分类] 材料工程

[关键词] Frost resistance;low-energy sulphoaluminate–belite cement;steel reinforcement corrosion.